Left panel: Completeness and contamination of the optical group catalog based on the Magneticum mock galaxy catalog. Central panel top: Comparison between the input halo mass M₂₀₀ and the group mass proxy based on the total luminosity scaled through the scaling relation of Popesso et al. (2005). The solid line indicates the 1:1 relation. The green symbols indicate the mean M₂₀₀ obtained in bins of 0.3 dex width of M_lum, whilst the error bar indicates the dispersion. Central panel bottom: Residuals Δ = log(M_lum)−log(M₂₀₀) of the individual (red) points and the mean values (green symbols). Right panel: Difference in ΔRA and ΔDec, estimated in kiloparsec, between the center of the detected optical group and the center of the input halo.